Acta Scientiarum Universitatis Pekiniensis (Naturalum)

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1 EPR AIRE FRAN kB LES Ee Bee 117

CHANGES IN BODY WEIGHT AND ORGAN WEIGHTS OF THE HEDGEHOG IN HIBERNATION AND IN FASTING

Iping Chao, C. J. Yeh and J. S. Ch’en (Laboratery of Animal and Human Physiology, _ Department of Biology, Peking University, Peking)

ABSTRACT

Under the circumstances of uninterrupted deep hibernation for periods cf three and half months in open air quarters, the body weight loss of the hedgehog proceeds at a rate of 1.04 g per day, or 1.37 g per day per kg.

During experimental fasting, the body weight suffers at first a rapid decrease for 1—2 days and then a more gradual diminution at a uniform rate, followed sooner or later by a terminating phase of a slow decline concurrent with a fall in body temperature to the level of the ambient temperature. The duration of fasting compatible to life varies with the initial body weight, a few days for the ordinary hedgehogs and a month or more for the exceptionally fat ones. During the period of uniform decrease, the rate of body weight loss is 11—15 g per day, slightly more in the samll animals. However, when the rate of loss is expressed in terms of g per day per kg body weight, it varies from 9g in the very fat animals of about 1300 g to as much as 54 g in the small ones between 200 and 300 g.

In general, the body weight loss of an ordinary hedgehog in hibernation is i—8% of that in experimental fasting.

About 80% of the body weight loss of the hedgehog in hibernation is accounted for by the disappearance of subcutaneous fat. The subcutaneous fat in the hedg> hog is subjected to large fluctuations, disappearing completely in the very much emaciated animals and accumulating in large amounts up to 25% body weight in the well-nourished ones. It is suggested that a thorough investigation of the characteristics of fat metabolism and its regulation in the hibernating mammals may be of considerable importance in the elucidation of the physiological mechanism of hibernation.